Search

The aeroelastic stability of an open cylindrical shell in subsonic airflow is analyzed. The equation of motion of the open cylindrical shell whose one surface is subjected to the subsonic airflow is established based on the Donnell shell theory and transformed into ordinary differential equations using Galerkin's method. The linear potential flow theory is applied to derive the aerodynamic pressure. The natural frequencies of the aeroelastic system are obtained, from which the flow velocity for the open cylindrical shell under instability can be calculated. The effects of the material and geometric parameters on the critical instability velocity are discussed. Furthermore, the open cylindrical shell is modelled using the finite element software ANSYS. The time domain responses of the structure in subsonic airflow are calculated using the two-way CFD/CSD (computational fluid-structure dynamics) coupled method. From the results, it can be seen that with the increase of the thickness and elastic modulus of the shell, the critical instability velocity increases also. The open cylindrical shell with a smaller radius shows better aeroelastic properties than that with a larger radius. The time domain responses obtained by the CFD/CSD method are compared with those calculated by the theoretical method, and the results of these two methods have a good agreement with each other. [ABSTRACT FROM AUTHOR]

The nonlinear vibrations of composite laminated plates with time-dependent base excitation and boundary conditions are investigated. According to the von Kármán nonlinear plate theory, the dynamic equations of motion of the laminated plates are established. The nonlinear partial differential equations are transformed to the nonlinear ordinary differential ones using the Bubnov-Galerkin's method. The primary resonance and the primary parametric resonance of the laminated plate with timedependent boundary conditions are investigated by means of the method of multiple scales. The validity of the present theoretical method is verified by comparing the amplitude-frequency relationship curves acquired from the present theoretical method with those calculated from the numerical simulation. The amplitude-frequency characteristic curves and the displacement time histories for different ply angles of the composite laminated plate are analyzed. The effects of the viscous damping factor and the transverse displacement excitation on the amplitude-frequency relationship curves are also studied. The present results are helpful for the nonlinear dynamical analysis and design of the composite laminated plate with time-dependent boundary conditions. [ABSTRACT FROM AUTHOR]